The disclosure generally relates to a power converter circuit and, more particularly, to the control circuit of the power converter circuit.
In many system designs, the power converter circuit must accurately and stably provide the power signal to ensure the correct operations of the system. The power converter circuit may adjust its operation by utilizing the feedback circuit or other suitable circuit structures for enhancing the stability and the accuracy of the power signal. For example, the filter circuit may be utilized as the feedback circuit in the power converter circuit.
The control circuit of the power converter circuit is usually realized with integrated circuit elements for reducing the hardware dimension. Some control circuits, however, need to place some of the circuit components outside the integrated circuit package of the control circuit (e.g., utilizing discrete circuit elements) to easily adjusting the gain, the frequency response, etc. of the feedback circuit. When the feedback circuit is placed outside the integrated circuit package of the control circuit, the dimension of the power converter increases and the dimension of the electronic product may not be effectively reduced. Moreover, the integrated circuit package of the control circuit needs to couple with the outside feedback circuit through the pin of the integrated circuit. The pin number of the integrated circuit package increases accordingly and a larger integrated circuit package might be needed. Therefore, the hardware dimension and the hardware cost increase when the feedback circuit is placed outside the integrated circuit package of the control circuit.
When the feedback circuit is placed in the integrated circuit package of the control circuit, the characteristic of the circuit elements of the feedback circuit may deviate from the required value during the manufacturing process of the integrated circuit elements. Sophisticated mechanism may be needed to adjust the feedback circuit to ensure the correct operations of the feedback circuit. For example, the pole or the zero of the feedback circuit may drift away from the designed value and the characteristic of the feedback circuit deteriorates because of the variation of the impedance value of the circuit elements in the feedback circuit. Thus, the impedance value of the circuit elements in the feedback circuit needs to be adjusted to ensure the feedback circuit operating correctly. When the feedback circuit is placed in the integrated circuit package of the control circuit, the pole or the zero of the feedback circuit may not be adjusted or not be adjusted accurately. The performance or the power converter circuit may therefore be affected and even not function normally. Moreover, when the feedback circuit is placed in the integrated circuit package of the control circuit, some of the circuit elements (e.g., the capacitors) may occupy a huge hardware area when implemented with integrated circuit elements. The hardware dimension therefore still may not be reduced effectively.